Pumps are known, e.g. from document FR 2 744 769, that have a diaphragm mounted in a propulsion chamber so as to undulate under drive from at least one linear electromagnetic actuator between two end plates that define a chamber for propelling fluid from an inlet of the pump towards an outlet of the pump.
The movable portion of the actuator is generally directly coupled to an outer edge of the diaphragm extending beside the inlet of the propulsion chamber and it imparts transverse oscillation to the outer edge of the diaphragm, thereby causing the diaphragm to undulate perpendicularly to its plane. The effect of coupling between the undulations and the fluid is to propel the fluid from the inlet towards the outlet of the propulsion chamber.
In general, the flow section for fluid in the propulsion chamber decreases from the inlet of the propulsion chamber towards the outlet of the pump, thus giving rise, because of flow rate conservation, to an acceleration of the fluid and thus to an increase in the mean speed of the fluid as measured in each cross-section of the propulsion chamber, which speed increases progressively from the inlet towards the outlet of the propulsion chamber.